Vision is accomplished through a complex process wherein light rays are refracted or bent so as to focus on the retina, which then transmits these signals through the fibers of the optic nerve to the brain. To function properly, the retina must contact the choroid, from which it receives a significant portion of the oxygen and glucose required for its normal nourishment. If the retina is detached from the choroid, it is therefore no longer able to accomplish its function.
Retinal detachment is typically the result of subretinal fluid that has permeated between the retina and the choroid through one or more holes in the structure of the retina. The retinal holes generally have the shape of either round holes or "horseshoe" shaped breaks. The permeated subretinal fluid causes portions of the retina to break away from the choroid. As a result of retinal detachment, patients observe some degree of reduction in their visual acuity and field of vision, dependent upon the extend of the retinal detachment.
Treatment of retinal detachment requires occlusion of the ruptures of the retina. In the prior art, occlusion is accomplished by suturing permanent silicone implants to the outer wall of the sclera. The implants cause a buckling or bulging in the sclera toward the area of the retinal holes. The buckling in the sclera causes the sclera and its internally contiguous layer, the choroid, to move inward and occlude the holes of the detached retina. After this occlusion occurs, subretinal fluid is reabsorbed, allowing the retina to settle back into position, in contact with the choroid. In order to induce an inflammatory reaction and augment the adhesiveness of the retina to its normal position in the areas in which it was previously detached, diathermy, cryotherapy, or laser therapy is also applied to the area of the retinal rupture.
This procedure for treating retinal detachment, however, presents several problems. For example, under this procedure, the patient is required to undergo general anesthesia. The surgery also demands a substantial amount of time. Moreover, because the procedure requires extensive surgical manipulation of ocular tissue, the patient is likely to suffer from pain and ocular edema in the post-operative period. Furthermore, substantial dexterity is needed in order to suture the solid implant to the patient's sclera.
Attempts to solve these problems have resulted in Lincoff's inflatable balloon. Prior Art FIG. 1 shows a representation of the Lincoff balloon during treatment of the detached retina. Lincoff's balloon is used to cause a buckling effect similar to that generated by the previously discussed solid permanent implants.
Referring now to FIG. 1 Prior Art, the prior art Lincoff balloon 12 is shown inserted in Tenon's space 14 near a detached retinal portion 18. In the Lincoff balloon technique, the balloon 12 is first inserted into Tenon's space 14 through an incision 20 in the conjunctiva 22. Once it is in a proper location in Tenon's space 14, the balloon 12 is inflated with a saline solution via a catheter 24. The catheter 24 further includes an intricate valve used to maintain the saline solution in the balloon 12. The balloon 12 is shown in FIG. 1 in a semi-inflated state. As the balloon 12 is further inflated, the sclera 26 buckles, this bulge causing the inner wall 32 of the sclera 26 to push the choroid 28 inward and make it to contact a detached retinal portion 18, specifically the portion where the retina holes are located. After the balloon 12 is inflated to the necessary degree, the catheter 24 is taped to the skin near the patient's eye. Several weeks later, after the detached retinal portion 18 has settled in contact with the choroid 28, the balloon 12 and catheter 24 are removed from the patient's eye.
Lincoff's balloon has many advantages over the solid permanent implants. For one, the surgery only requires local anesthesia and surgical time is reduced. Secondly, during the operation, the size of the buckle effect is easily graduated depending on the volume of liquid injected inside the balloon. Also, less tissue manipulation is necessary to insert the balloon, and it is not normally necessary to suture the balloon to the sclera. Finally, diplopia and muscle imbalance does not occur after balloon removal.
The Lincoff balloon, however, also presents several problems. Primarily, the Lincoff balloon is inflated by a catheter which requires an intricate valve to maintain the saline solution in the balloon. After the balloon is inserted and inflated in the Tenon's space of the patient's eye, the catheter protrudes from the patient's eye, disturbing normal eyelid movements and possibly causing corneal erosions. Moreover, the catheter is taped to the patient's skin during the several weeks following the procedure, which adds to the patient's inconvenience and annoyance.
Therefore, a need exists for an inflatable balloon for use in retinal detachment surgery that does not require a catheter and valve as integral components of the balloon.